Medication profiles mainly focused on possible drug-drug and drug-disease interactions, with some drug duplications. To do the medication profiles we licensed a proprietary computerized retrospective drug utilization review system. We randomly assigned over 900 patients to Usual Care or Provider Feedback. For patients in the latter group, selected providers were contacted by letter with pertinent information; electronic mail was used for follow-up contact. Clinical and other relevant data was retrospectively abstracted from the medical records for up to one year from the last medication profile for all patients. This was done by a pharmacist reviewer, using a study-derived instrument, and blinded to patient assignment. ADE incidence is the primary outcome of interest, with other outcomes such as ADE severity and preventability also assessed. We also developed and implemented provider surveys in pre- and post-profiling periods.